Proposal to revise the limits for rolling resistance and wet grip, address tyres for vintage vehicles, and revise the definition for special-use C1 tyres.

Proposal to bring the latest ISO 10844 standard test surface into the Regulation.

Proposal to address the definition of the radial structure (as a continuation to ECE/TRANS/WP.29/GRBP/2021/9), the definition of snow tyres, the requirements for special use tyres of class C1, the addition of an optional prefix for extra load tyres, a clarification of the description of the load/speed test for run flat tyres and extended mobility tyres (EMT) and editorial corrections.

Proposal from the Worn Tyres working group to improve precision of the test procedures for measuring the wet adhesion of tyres in a worn state by using a moulded SRTT16 reference tyre (instead of a buffed tyre), to introduce new transitional provisions related to this change, to extend corrections already made to thee 02 series to the 03 series and make additional editorial corrections, and to define the range for tyre inflation vis-à-vis rim size to reduce uncertainties in measuring tread depth.

Proposal from the Worn Tyres working group to set the wet grip index threshold at 0.80 for class C1 tyres with a nominal aspect ratio equal to or less than 40, a section width equal to or higher than 235 mm and suitable for speeds equal to or greater than 300 km/h and for class C1 all terrain and special use tyres (see GRBP-75-27, slide 6). The proposal also introduces the k_worn factor in a new para. 3 in Annex 9 to address wet grip of C2 and C3 tyres in a worn state (see GRBP-75-26-Rev.1 for concept).

Proposal to introduce a new definition of traction elements to characterize traction tyres.

Proposal to correct editorial mistakes in document GRBP/2021/17 that were not corrected by informal document GRBP74-31-Rev.1.

Proposal to introduce provisions to allow type approval of special use tyres that fulfil the requirements for snow performance as laid out in Annex 7. The respective marking related to the “Alpine” symbol has been considered for tyres complying with these requirements.